With increasing concern of ocean acidfification due to increasing atmospheric CO2 levels, calcifying organisms such as molluscs are faced with harsh conditions. Although many studies have assessed water column pH, none assess the pH of habitats that many of these organisms experience directly. Thus, my research focuses on the effects surface sediment pH and calcium carbonate availability on the settlement and recruitment of soft-shell clams (Mya arenaria) in the Bay of Fundy.